JPH0773953B2 - Photosensitive lithographic printing plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photosensitive lithographic printing plate, and more specifically, it is excellent in ink receptivity, printing durability, water retention and hydrophilicity, and does not cause scumming. And a photosensitive lithographic printing plate having good storage stability.

[Conventional technology]

Conventionally, aluminum is most often used as a support for lithographic printing plates. This is another support-paper,
This is because it is comprehensively superior in lightness, low cost, elasticity and strength as compared with iron, film and the like.

By the way, the lithographic printing plate is composed of an oil-sensitive image area and a hydrophilic non-image area, and in order to use aluminum as a support, graining is usually performed and the surface is roughened, It is necessary to improve hydrophilicity.

Further, in order to use it as a printing plate, in addition to excellent hydrophilicity and water retention, it is required to have good oil sensitivity and high printing durability. Has been done.

[Problems to be solved by the invention]

Grain with a highly uneven surface shape has relatively little abrasion of the photosensitive layer and generally has high printing durability, but when the thickness of the photosensitive layer is thin or thin, the tip of the grain becomes It is exposed on the surface and the oil sensitivity is poor. In particular, gum removability becomes poor.

On the other hand, a uniform and dense grain with relatively few irregularities has a good oil sensitivity, but has a problem in the adhesiveness to the photosensitive layer.

An object of the present invention is to provide a photosensitive lithographic printing plate having improved water retention, hydrophilicity, storage stability, ink receptivity and printing durability.

[Means for solving problems]

Briefly describing the present invention, the present invention relates to a photosensitive lithographic printing plate, having an anodized layer on the surface in an amount of 5 to 35 mg / dm ² , and having a center line average roughness (Ra) of 0.4. ~ 0.9 μm,
On an aluminum support having a rough surface with a non-porosity of 50% or less according to an Abbott load curve at a depth three times Ra.
A photosensitive layer containing a diazo resin and a lipophilic polymer compound as a main component is provided in an amount of 10 to 40 mg / dm ² , and the lipophilic polymer compound is a hydroxyl group-containing acrylamide, methacrylamide, or acryl. It is characterized in that it contains a constitutional unit derived from at least one monomer selected from the group consisting of acid esters and methacrylic acid esters.

The present inventors have found that the roughened aluminum surface shape and the thickness of the anodized layer satisfy specific conditions, and the diazo resin and the photosensitive layer containing the specific polymer compound as a main component are used. The present invention has been completed by discovering that the above-mentioned requirements are satisfied when the film thickness has a certain range.

The present invention will be described below. As the aluminum support used in the present invention, a plate or foil of pure aluminum or aluminum alloy is suitable. As the aluminum alloy, various ones can be used, for example, silicon, iron, copper,
Alloys with metals such as manganese, magnesium, chromium, zinc, lead, bismuth and nickel are used.

In the present invention, such a support has a surface area of 5 to 35 mg / d.
m ² has an anodized layer and has a center line average roughness Ra of
0.4 to 0.9 μm, preferably 0.5 to 0.8 μm, and Ra
The non-porosity (hereinafter referred to as "Abbott load characteristics") according to the Abbott load curve at a depth three times as high as 50% or less,
Preferably, it has a rough surface of 35% or less.

When Ra is less than 0.4 μm, the water retention of the printing plate becomes insufficient, and if the amount of water supplied changes during printing, stains will be generated immediately. When it exceeds 0.9 μm, the water retention property is good, but the halftone dot reproducibility of the printing plate deteriorates.

Abbott load characteristics correlate with printing durability, and the smaller this value, the lower the density of flat parts on the roughened surface, which is an essential condition for high printing durability. Becomes

These points will be described with reference to the accompanying drawings.

FIG. 1 and FIG. 2 are schematic diagrams for explaining the relationship between the rough surface shape and the Abbott load characteristic, and (a) and (b).
Represents a stylus chart, and (A) and (B) represent an abbot load curve. (A), (b), (A) and (B)
In, the vertical axis represents the depth of the rough surface. Further, in (A) and (B), the horizontal axis represents the non-porosity.

For example, the Abbott load curve of a rough surface (type 1) having a small number of flat portions on the surface as shown in FIG. 1 (a) is a curve as shown in (A). On the other hand, the abbot load curve of a rough surface (type 2) having many flat parts on the surface as shown in FIG. 2B becomes a curve as shown in FIG. The non-porosity at a constant depth can be obtained from each of these curves.

For example, type 1 has a non-porosity of 25% at a depth of 2 μm.
It can be seen that it is about 75% for Type 2.

The abbot load curve is determined according to the method described in German standard DIN 4762-3.2.3.3.

The amount of the anodized layer on the surface of the support in the invention, the a 5-35 mg / dm ² as, what is 8~30mg / dm ² is preferred from the viewpoint of printing durability.

When the amount of the anodized layer is less than 5 mg / dm ² , the non-image area is easily worn and the printing durability is deteriorated. On the other hand, if the amount of the anodized layer exceeds 35 mg / dm ² , the degree of wear of the non-image area is
Almost unchanged and impractical.

The support having a rough surface having the above characteristics can be obtained by appropriately selecting and combining the conditions of polishing treatment and further anodizing treatment.

As the polishing method, various methods such as ball polishing, brush polishing, chemical polishing, electrolytic polishing, polishing by liquid honing, buff polishing, and combinations thereof can be applied. As the abrasive used in the mechanical polishing method, alumina, silicon carbide, chromium oxide, red iron oxide, tungsten carbide, boron carbide, sand, silica stone,
Examples include steel balls.

Specifically, 1 to 1 aluminum alloy plate (material 1100 etc.)
After lightly surface-treating with 10% caustic soda solution to remove oxide layer, adhering fats and oils, contaminants, etc., the surface is roughened by brush-polishing with the above-mentioned abrasive such as sand with a nylon brush. To do.

As the method of etching by electrolysis, 0.1% of hydrochloric acid, citric acid, nitric acid, boric acid, oxalic acid or a mixture thereof is used.
Applied voltage 10 ~ 100V, current density 1 ~ 10 in ~ 10% aqueous solution
Select from the range of 0 A / dm ² , bath temperature 10 to 50 ° C., and electrolysis time 3 to 300 seconds.

Particularly preferred is a bath containing nitric acid or hydrochloric acid as a main component.

Before performing the polishing treatment, it is desirable to perform degreasing and cleaning beforehand. As an example of degreasing treatment, petroleum solvent or trichlorethylene, solvent degreasing to remove stains using chlorinated hydrocarbons such as perchlorethylene, nonionic surfactant and trichlorethylene, solvent such as kerosene and water Examples include emulsification degreasing using an emulsified solution, alkaline degreasing boiling with a treatment liquid containing an alkaline chemical, electrolytic degreasing, and the like.

Since a smudge is generated on the surface of the roughened substrate, it is desirable to remove the smat by etching the surface with an acid or an alkali.

As the acid, sulfuric acid, phosphoric acid, hydrofluoric acid, nitric acid, hydrochloric acid or the like is used.

As the alkali, sodium hydroxide, potassium hydroxide, tribasic sodium phosphate, tribasic potassium phosphate, sodium aluminate, sodium metasilicate, sodium carbonate or the like is used.

Next, the aluminum plate is anodized.

The anodizing treatment is carried out by applying a direct current or an alternating current to aluminum in an aqueous solution of sulfuric acid, phosphoric acid, oxalic acid, chromic acid or the like or a combination of two or more thereof. At this time, the concentration of the electrolytic solution is selected from the range of 1 to 70%, the liquid temperature of 10 to 65 ° C., the current density of 1 to 60 A / dm ² , the applied voltage of 1 to 100 V, and the electrolysis time of 10 seconds to 10 minutes.

Particularly, good results are obtained when anodizing treatment is performed in phosphoric acid or an electrolytic solution containing phosphoric acid as a main component. For example, an aluminum plate in an aqueous solution containing 10 to 50% by weight, preferably 20 to 40% by weight of phosphoric acid, or 25% by weight of such phosphoric acid and total acid.
A bath temperature of 10% by weight or less, preferably 10% by weight or less, in an aqueous solution containing another acid, for example, a mixed acid with sulfuric acid, oxalic acid, or the like.
~ 50 ° C, preferably 25-45 ° C, current density 0.2-10A / d
m ² , preferably 1 to 7 A / dm ² , 10 seconds to 10 minutes, preferably 20 seconds to 3 minutes, the average pore diameter of the obtained anodized layer is 200 ~ 900Å, preferably 300 ~ 900Å, particularly preferably 400-900Å, with a pore density of 100-1,000 / μm ² ,
100 to 500 pieces / μm ² , particularly preferably 100 to 3
Use the one that has been subjected to anodization so that the number becomes 50 / μm ² .

The anodized aluminum plate is usually further added to water or a weak acid or weak alkaline aqueous solution at 10 to 100 ° C. and 10 to 6 ° C.
It is processed under the condition of 00 seconds. After that, a hydrophilic treatment is applied.

Examples of the hydrophilic treatment include hot water sealing and sodium silicate treatment, but sodium silicate treatment is preferable from the viewpoints of adhesiveness, diazo residue and developability. The conditions for the sodium silicate treatment are as follows.
It is performed by immersing at 0 ° C to 95 ° C for 10 seconds to 5 minutes. Preferably, after that, it is immersed in water at 60 ° C to 100 ° C for 10 seconds to 5 minutes for treatment.

The photosensitive layer coated on the support has a lipophilic polymer compound and a diazo resin as main components, and the coating amount is 10 to
40 mg / dm ^2, preferably selected from the range of 10 to 30 mg / dm ^2. If the coating amount is less than 10 mg / dm ² , the tips of the grains will partially project and the oil sensitivity will be poor, while if it is over 40 mg / dm ² , the sensitivity will be significantly reduced and the developability will also be poor. Becomes

The diazo resin is preferably a condensate of a substituted or unsubstituted p-diazodiphenylamine and an aldehyde, and an anion of which is a halogenated Lewis acid such as PF ₆ or BF ₄ , and particularly preferably the following general formula: 20 mol% or more of the resin represented by I and having n in the formula of 5 or more, preferably,
A diazo resin containing 20 to 60 mol% is preferable.

(In the formula, R ¹ , R ² and R ³ represent hydrogen, an alkyl group or an alkoxy group, R represents hydrogen, an alkyl group or a phenyl group, X represents PF ₆ or BF ₄ , and n is 1 to 200. In addition, for example, Japanese Examined Patent Publication No. 47-1167 or U.S. Pat. No. 33
Those in which the anion described in 00309 is an organic acid can also be used.

As the lipophilic polymer compound, a lipophilic polymer compound having a hydroxyl group is preferable from the viewpoint of storage stability. Examples of the lipophilic polymer compound having a hydroxyl group that can be used for this purpose include, for example, those derived from monomers such as acrylamides, methacrylamides, acrylic acid esters or methacrylic acid esters having a hydroxyl group as described below. And a copolymer having a molecular weight of 20,000 to 200,000, which contains the structural unit.

(1) A monomer having an aromatic hydroxyl group, for example, N-
(4-hydroxyphenyl) acrylamide or N-
(4-hydroxyphenyl) methacrylamide, o-, m
-, P-Hydroxystyrene, o-, m-, p-hydroxyphenyl-acrylate or methacrylate (2) Monomer having aliphatic hydroxyl group, for example, 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate Other monomer to be copolymerized Examples include (1) α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, etc. (2) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate,
(Substituted) alkyl acrylates such as hexyl acrylate, octyl acrylate, 2-chloroethyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, N-dimethylaminoethyl acrylate (3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl Methacrylate,
(Substituted) alkylmethacrylates such as amylmethacrylate, cyclohexylmethacrylate, 2-hydroxyethylmethacrylate, 4-hydroxybutylmethacrylate, glycidylmethacrylate, N-dimethylaminoethylmethacrylate (4) acrylamide, methacrylamide, N-methylolacrylamide, N-methylol Acrylamide such as methacrylamide, N-ethylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N-ethyl-N-phenylacrylamide, etc. Or methacrylamides (5) ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxy Vinyl ethers such as ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether (6) Vinyl acetate, vinyl chloroacetate,
Vinyl esters such as vinyl butyrate and vinyl benzoate (7) Styrenes such as styrene, α-methylstyrene, methylstyrene and chloromethylstyrene (8) Methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, phenyl vinyl Vinyl ketones such as ketones (9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene (10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like, In addition, any monomer that can be copolymerized with a monomer having a hydroxyl group may be used, and the present invention is not limited thereto. In addition to these, polyvinyl butyral resin, polyurethane resin, polyamide resin, epoxy resin, novolak resin, natural resin and the like may be added if necessary.

The lipophilic polymer compound having a hydroxyl group used in the present invention is usually contained in the solid content of the photosensitive composition in an amount of 40 to 99% by weight, preferably 50 to 95% by weight. The diazo resin is usually contained in an amount of 1 to 60% by weight, preferably 3 to 30% by weight.

Various known additives shown below can be added to the photosensitive composition of the present invention in order to further improve the performance.

(1) Dyes for visualizing images (2) Fluorine-based surfactants and alkyl ethers for improving coating properties (3) Add flexibility and abrasion resistance to coating films Plasticizer for (4) Oil sensitizer (5) Stabilizer The addition amount of these is generally 0.01 to 30% by weight based on the total solid content.
Is.

The developing solution used for the developing treatment of the photosensitive lithographic printing plate according to the present invention may be any known one, but preferably the following. That is, as the current developing solution for the photosensitive printing plate according to the present invention, water or an aqueous solution containing a specific organic solvent and / or an alkaline agent can be mentioned. Here, the specific organic solvent is capable of dissolving or swelling the non-exposed area (non-image area) of the above-mentioned photosensitive composition layer when contained in a developing solution, and is water at room temperature (20 ° C). Refers to an organic solvent having a solubility of 10% by weight or less. Such an organic solvent only needs to have the above-mentioned characteristics, and is not limited to the following, but if these are exemplified, for example, ethyl acetate,
Carboxylic esters such as propyl acetate, butyl acetate, amyl acetate, benzyl acetate, ethylene glycol monobutyl acetate, butyl lactate, butyl levulinate;
Ketones such as ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone; such as ethylene glycol monobutyl ether, ethylene glycol pentyl ether, ethylene glycol monophenyl ether, benzyl alcohol, methyl phenylcarbinol, n-amyl alcohol, methyl amyl alcohol Alcohols; alkyl-substituted aromatic hydrocarbons such as xylene; halogenated hydrocarbons such as methylene dichloride, ethylene dichloride and monochlorobenzene. One or more of these organic solvents may be used. Among these organic solvents, ethylene glycol monophenyl ether and benzyl alcohol are particularly effective. In addition, the content of these organic solvents in the developer is approximately 1 to
It is 20% by weight, and more preferable results are obtained especially at 2 to 10% by weight.

On the other hand, as the alkaline agent contained in the developer, (A) sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, sodium or ammonium salt of secondary or tertiary phosphate, Inorganic alkaline agents such as sodium metasilicate, sodium carbonate and ammonia (B) Mono, di or trimethylamine, mono, di or triethylamine, mono or diisopropylamine, n
-Butylamine, mono-, di- or triethanolamine,
Examples thereof include organic amine compounds such as mono-, di- or triisopropanolamine, ethyleneimine, and ethylenediamine.

The content of these alkaline agents in the developer is usually 0.05.
-4% by weight, preferably 0.5-2% by weight.

Further, in order to further improve storage stability, printing durability and the like, it is preferable to include a water-soluble sulfite in the developer. As such a water-soluble sulfite, an alkali or alkaline earth metal salt of sulfite is preferable, and examples thereof include sodium sulfite, potassium sulfite, lithium sulfite and magnesium sulfite. The content of these sulfites in the developer composition is usually 0.05 to 4% by weight, preferably 0.1 to 1% by weight.

Further, a certain solubilizing agent may be contained in order to assist the dissolution of the above organic solvent in water. As such a solubilizing agent, in order to realize the intended effect of the present invention, it is preferable to use a low molecular weight alcohol or ketone which is more soluble in water than the organic solvent used. Moreover, an anion activator, an amphoteric activator, etc. can also be used. Examples of such alcohols and ketones include methanol, ethanol, propanol, butanol, acetone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methoxybutanol, ethoxybutanol, 4-methoxy-4-methylbutanol, N. -It is preferable to use methylpyrrolidone or the like. Further, as the activator, for example, sodium isopropylnaphthalene sulfonate, sodium n-butylnaphthalene sulfonate, sodium N-methyl-N-pentadecylaminoacetate, sodium lauryl sulfate, and the like are preferable. The amount of the solubilizer such as alcohol or ketone used is not particularly limited, but is generally preferably about 30% by weight or less based on the entire developer.

The photosensitive lithographic printing plate according to the present invention is, after imagewise exposure, brought into contact with the above-mentioned developing solution or rubbed, and after about 10 to 60 seconds at room temperature to 40 ° C., the photosensitive composition The photosensitive composition in the non-exposed area is completely removed without adversely affecting the exposed area of the physical layer.

The production examples of the grain, diazo resin and polymer used in the present invention are shown below.

(Production of Grain) Nine kinds of aluminum supports having different polishing conditions and anodizing conditions were produced. The manufacturing conditions and the shape of the obtained grain are shown in Table 1 below.

Numbers 1 to 3 are brush-polished products, and numbers 4 to 7 and 9
Is an electrolytic etching in a bath composition mainly containing hydrochloric acid or nitric acid. No. 8 is electrolytic etching in nitric acid bath after brush polishing.

In addition, after polishing and anodizing, all the sand grains were immersed in a 1% sodium metasilicate solution at 85 ° C for 3 minutes to be treated with sodium silicate, and then immersed in hot water at 90 ° C for 2 minutes. did.

The Ra and abbot load characteristics were measured using a stylus type persometer [RTK-50, manufactured by PERTHEN].

(Synthesis of Polymer 1) N- (4-hydroxyphenyl) methacrylamide 10.0
g, acrylonitrile 25 g, ethyl acrylate 60 g, methacrylic acid 5 g and azobisisobutyronitrile 1.642 g were dissolved in acetone-methanol 1: 1 mixed solvent 112 ml, and after nitrogen substitution, the mixture was heated at 60 ° C. for 8 hours.

After the completion of the reaction, the reaction solution was poured into water 5 with stirring, and the resulting white precipitate was dried to obtain 90 g of polymer 1.

When the molecular weight of this polymer was measured by gel permeation chromatography (hereinafter abbreviated as GPC), the weight average molecular weight was 85,000.

(Synthesis of Polymer 2) 2-hydroxyethyl methacrylate 45 g, acrylonitrile 10 g, ethyl methacrylate 45 g, methacrylic acid 2 g
And 1.2 g of benzoyl peroxide were added dropwise to 300 g of ethylene glycol monomethyl ether heated to 100 ° C. over 2 hours. After completion of the dropping, 300 g of ethylene glycol monomethyl ether and 0.3 g of benzoyl peroxide were added and the reaction was continued for 4 hours. After completion of the reaction, the mixture was diluted with methanol, poured into water 5 with stirring, and the white precipitate formed was dried to obtain 93 g of polymer 2.

When the molecular weight of this polymer was measured by GPC,
The weight average molecular weight was 65,000.

(Synthesis of Polymer 3) Methyl methacrylate (60 g), acrylonitrile (30 g), methacrylic acid (10 g) and azobisisobutyronitrile (1.5 g) were dissolved in methylcellosolve (200 g) and polymerized at 80 ° C. for 4 hours under a nitrogen atmosphere. The reaction mixture was added dropwise to 5 of water and the white precipitate formed was dried to give Polymer 3
g got.

When the molecular weight of this polymer was measured by GPC, the weight average molecular weight was 60,000.

(Synthesis of polymer 4) 45 g of 2-hydroxyethyl methacrylate, 20 g of acrylonitrile, 30 g of methyl methacrylate, 5 g of methacrylic acid
Was polymerized in the same manner as in the synthesis example of polymer 3 to obtain polymer 4.

When the molecular weight of this polymer was measured by GPC, the weight average molecular weight was 63,000.

(Synthesis of diazo resin-1) 14.5 g (50 mmol) of p-diazodiphenylamine sulfate was dissolved in 40.9 g of concentrated sulfuric acid under ice cooling. 1.2 g (40 mmol) of paraformaldehyde was slowly added dropwise to this reaction solution. At this time, the reaction temperature was added so that the temperature did not exceed 10 ° C. After that, stirring was continued for 2 hours under ice cooling.

The reaction mixture was added dropwise to 500 ml of ethanol under ice cooling, and the formed precipitate was passed through. After washing with ethanol, the precipitate was dissolved in 100 ml of pure water, and to this solution was added a cold concentrated aqueous solution containing 6.8 g of zinc chloride. After passing through the generated precipitate, it was washed with ethanol and dissolved in 150 ml of pure water. To this solution was added a cold concentrated aqueous solution in which 8 g of ammonium hexafluorophosphate was dissolved. The resulting precipitate was collected, washed with water, and dried at 30 ° C for one day to obtain diazo resin-1.

When the molecular weight of this diazo resin-1 was measured by GPC, it contained about 35 mol% of a pentamer or more.

(Synthesis of diazo resin-2) Synthesized in the same manner as diazo resin-1, and treated with an aqueous solution in which 15 g of 2-hydroxy-4-methoxy-benzophenone-5-sulfonic acid was dissolved in place of the final ammonium hexafluorophosphate. Diazo resin-2 was obtained.

When this diazo resin-2 was measured by GPC, it contained about 32 mol% of a pentamer or more.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to these examples.

Examples 1 to 5 and Comparative Examples 1 to 3 Photosensitive liquid-1 having the following composition was applied to the sands 1 to 8 obtained in the above production example using a whirler. Then, it was dried at a temperature of 85 ° C. for 3 minutes to obtain a photosensitive lithographic printing plate. The coating amount was 2.0 g / m ^{2 as a} dry weight.

(Photosensitive liquid-1) The photosensitive lithographic printing plate obtained was 60 cm with a 3 KW ultra-high pressure mercury lamp.
Was exposed for 30 seconds from the above distance and developed with Developer-1 to obtain a lithographic printing plate.

(Developer-1) The sensitivity and printing durability of the obtained lithographic printing plate were measured. The results are shown in Table 2.

The printing durability was defined as the number of sheets printed on a high-quality paper with a sheet-fed offset printing machine, and the number of sheets in which flat screen scraping or defective inking occurred.

It was found from Table 2 that the printing plate according to the present invention has high printing durability.

Grains 1 and 2 using phosphoric acid as an anodizing electrolyte
As far as it can be judged from the discoloration of the plate at the time of printing 300,000 sheets,
Particularly high printing durability.

To examine the storage stability, the plates of Examples 1 and 2 were
It was left under constant temperature and humidity conditions of 40 ° C. and RH80% for 3 days, developed with Developer-1 and applied to a printing machine to obtain an image with no stain and good image reproducibility.

Example 6 and Comparative Example 4 Photosensitive liquid-2 having the following composition was applied to the grain-2 obtained in the above production example by using a whirler. Then, it was dried at a temperature of 85 ° C. for 3 minutes to obtain a photosensitive lithographic printing plate. The dry coating weight was 20 mg / dm ² (Example 6) and 8 mg / dm ² (Comparative Example 4).
I got two of them.

(Photosensitive liquid-2) The photosensitive lithographic printing plate obtained was 60 cm with a 3 KW ultra-high pressure mercury lamp.
Was exposed for 30 seconds from the above distance and developed with Developer-1 to obtain a lithographic printing plate.

The lithographic printing plate thus obtained was applied to an offset printing machine (Roland Co., Barba RP-1) to compare the initial ink receptivity.
The results are shown in Table 3.

It can be seen that the plate having a coating amount of 8 mg / dm ² is defective, especially when imprinted.

Examples 7 and 8 and Comparative Example 5 Photosensitive liquids-3, 4, and 5 having the following compositions were applied to the grain-1 obtained in the above Production Example using a whirler. afterwards
It was dried at a temperature of 85 ° C. for 3 minutes to obtain a photosensitive lithographic printing plate. The coating amount was 16 mg / dm ² in terms of dry weight.

The sensitivity, printing durability, and storage stability were measured, and the results are shown in Table 4.

(Photosensitive liquid-3,4,5) Example 9 Photosensitive liquid 6 having the following composition was applied to the grain-9 obtained in the above Production Example by using a whirler. Then, it was dried at a temperature of 85 ° C. for 3 minutes to obtain a photosensitive lithographic printing plate. The coating amount was 2.0 g / m ^{2 as a} dry weight.

(Photosensitive liquid-6) After storing at 40 ° C and RH80% for 3 days, it was exposed, developed, and printed on a fine paper by a sheet-fed offset printing machine, but it did not stain and showed a printing durability of 300,000 sheets or more.

〔The invention's effect〕

As described above, according to the present invention, a diazo resin and a photosensitive layer containing a specific polymer compound as a main component are formed on an aluminum support having an anodized layer having a specific thickness and a specific rough surface. , By providing a specific thickness, water retention,
A remarkable effect that a photosensitive lithographic printing plate having excellent hydrophilicity, good storage stability, excellent ink receptivity and excellent printing durability can be provided.

[Brief description of drawings]

1 and 2 are schematic diagrams for explaining the relationship between the rough surface shape and the abutment load characteristic in the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor St. Goto No. 1 Sakura Town, Hino City, Tokyo Photo Konishi Roku Photo Industry Co., Ltd. (72) Norito Suzuki No. 1, Sakura Town, Tokyo Hino City Photo Roku Konishi Photo Co., Ltd. In-house (56) References JP 59-182967 (JP, A) JP 50-124705 (JP, A)

Claims (4)

[Claims] 1. An Abbott load curve having an anodized layer in an amount of 5 to 35 mg / dm ² and having a center line average roughness (Ra) of 0.4 to 0.9 μm and a depth three times Ra. The non-porosity due to
A photosensitive layer containing a diazo resin and a lipophilic polymer as main components is provided on an aluminum support having a rough surface of 50% or less.
At least 40 mg / dm ² , and the lipophilic polymer compound is at least one selected from the group consisting of acrylamides having a hydroxyl group, methacrylamides, acrylic esters and methacrylic esters. A photosensitive lithographic printing plate comprising a constitutional unit derived from the above monomer. 2. The photosensitive lithographic printing according to claim 1, wherein the diazo resin is a condensate of a substituted or unsubstituted p-diphenylamine and an aldehyde, and the anion of which is PF ₆ or BF _4. Edition. 3. The diazo resin has the following general formula I: (In the formula, R ¹ , R ² and R ³ represent a hydrogen atom, an alkyl group or an alkoxy group, R represents a hydrogen atom, an alkyl group or a phenyl group, X represents PF ₆ or BF ₄ , and n is 1 The photosensitive lithographic printing plate according to claim 1, further comprising 20 mol% or more of a resin represented by the formula: 4. The anodic oxide layer has an average pore diameter of 200 to 900Å obtained by anodizing in phosphoric acid or an electrolyte solution containing phosphoric acid as a main component, and a pore density of 100 to 1000 pieces / μm. The photosensitive lithographic printing plate according to claim 1, wherein the anodic oxide layer is ² .